| 摘要 |
PURPOSE:To miniaturize an optical fiber sensor by detecting a liquid level from the angle and refractive index of a prism installed on an end surface or tip of an optical fiber and mutual relation with a medium. CONSTITUTION:One-end surfaces of two optical fibers 1 and 2 made of, for example, polymethyl methacrylate resin are cut slantingly at 45 deg. to form slanting surfaces 1b and 2b, and the 1st optical fiber 1 and the 2nd optical fiber 2 are adhered on those slanting surfaces 1a and 2b in a V shape. Light is reflected totally by the slanting surface 1b of the 1st optical fiber 1 in air to enter the slanting surface 2b of the 2nd optical fiber 2 and is reflected upward into the optical fiber 2. When the tip part is in water, the light incident on the 1st optical fiber 1 is transmitted through the slanting surface 1b to travels straight. Thus, reflection and transmission on the slanting surface 1b are determined according to the difference in refracting index of a medium, so the liquid level of water, etc., is detected from whether or not the light incident from the end surface 1a of the 1st optical fiber is projected from the end surface 2a of the 2nd optical fiber 2. |
